<!DOCTYPE html>
<html lang="en" style="font-size: 20px;">

<head>
    <meta charset="UTF-8"> 
    <meta name="viewport"
        content="width=device-width, user-scalable=no,initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <title>Document</title>
    <style type="text/css">
        .box01 {
            font-size: 12px;
            width: 20rem;
            height: 10rem;

            background-color: gold;
        }

        .box02 {
            font-size: 20px;
            width: 20rem;
            height: 10rem;

            background-color: green;
        }
    </style>
</head>

<body>
    <div class="box01"></div>
    <br />
    <br />

    <div class="box02"></div>

</body>

</html>